PLASTIC BRONCHITIS: A RARE COMPLICATION FOLLOWING A MOTOR VEHICLE COLLISION

Plastic bronchitis, more appropriately termed chyloptysis, is a rare and potentially fatal condition caused by chylous coating of the airways. These cast coating can dislodge and become an obstructive mass in the patient's airway, necessitating rapid intervention. PB is well described to occur following single ventricle physiology heart disease corrective procedures, particularly following Fontan procedures. It is less commonly seen in traumatic settings. We present the youngest known case of a traumatic injury induced plastic bronchitis. A 19-year-old man was involved in a motor vehicle accident with airbag deployment. The airbags struck him in the chest; however, the patient felt well at the time and did not seek medical attention. Several months later the patient began coughing up milky white masses identified as casts. He was initially diagnosed with asthma but did not respond to therapy. He ultimately was found to have evidence of thoracic duct injury. Options for therapy were discussed, including possible thoracic duct ligation. The patient opted to continue a low-fat diet and has remained cast free. This case highlights the importance of considering plastic bronchitis in patients with cast production and a history of trauma to the chest.

Plastic bronchitis: A rare complication following a motor vehicle collision

Plastic bronchitis, more appropriately termed chyloptysis, is a rare and potentially fatal condition caused by chylous coating of the airways. These cast coating can dislodge and become an obstructive mass in the patient's airway, necessitating rapid intervention. PB is well described to occur following single ventricle physiology heart disease corrective procedures, particularly following Fontan procedures. It is less commonly seen in traumatic settings. We present the youngest known case of a traumatic injury induced plastic bronchitis. A 19-year-old man was involved in a motor vehicle accident with airbag deployment. The airbags struck him in the chest; however, the patient felt well at the time and did not seek medical attention. Several months later the patient began coughing up milky white masses identified as casts. He was initially diagnosed with asthma but did not respond to therapy. He ultimately was found to have evidence of thoracic duct injury. Options for therapy were discussed, including possible thoracic duct ligation. The patient opted to continue a lowfat diet and has remained cast free. This case highlights the importance of considering plastic bronchitis in patients with cast production and a history of trauma to the chest.

Variant ataxia-telangiectasia presenting as primary-appearing dystonia in Canadian Mennonites

OBJECTIVE

To compare the phenotype of primary-appearing dystonia due to variant ataxia-telangiectasia (A-T) with that of other dystonia ascertained for genetics research.

METHODS

Movement disorder specialists examined 20 Canadian Mennonite adult probands with primary-appearing dystonia, as well as relatives in 4 families with parent-child transmission of dystonia. We screened for the exon 43 c.6200 C>A (p. A2067D) ATM mutation and mutations in DYT1 and DYT6. Clinical features of the individuals with dystonia who were harboring ATM mutations were compared with those of individuals without mutations.

RESULT

Genetic analysis revealed a homozygous founder mutation in ATM in 13 members from 3 of the families, and no one harbored DYT6 or DYT1 mutations. Dystonia in ATM families mimicked other forms of early-onset primary torsion dystonia, especially DYT6, with prominent cervical, cranial, and brachial involvement. Mean age at onset was markedly younger in the patients with variant A-T (n = 12) than in patients with other dystonia (n = 23), (12 years vs 40 years, p < 0.05). The patients with A-T were remarkable for the absence of notable cerebellar atrophy on MRI, lack of frank ataxia on examination, and absence of ocular telangiectasias at original presentation, as well as the presence of prominent myoclonus-dystonia in 2 patients. Many also developed malignancies.

CONCLUSION

Ataxia and telangiectasias may not be prominent features of patients with variant A-T treated for dystonia in adulthood, and variant A-T may mimic primary torsion dystonia and myoclonus-dystonia.

Olfactory dysfunction in LRRK2 G2019S mutation carriers

BACKGROUND

Olfactory dysfunction is an established nonmotor feature of idiopathic Parkinson disease (PD), which may precede disease onset. Olfaction is likely disturbed in patients with PD with leucine-rich repeat kinase (LRRK2) G2019S mutations, although the degree of impairment is debated. It is also unclear whether mutation carriers who have not yet manifested with PD have olfactory disturbances.

METHODS

Thirty-one subjects with LRRK2 G2019S mutation-related PD (PD-manifesting carriers [PD-MC]), 30 subjects with PD without mutations (PD noncarriers [PD-NC]), 28 mutation carrier family members (nonmanifesting carriers [NMC]), and 46 controls completed the University of Pennsylvania Smell Identification Test (UPSIT). Generalized estimating equations were applied to determine whether olfactory score was associated with PD and LRRK2 mutation status.

RESULTS

As expected, having PD was associated with impaired olfaction regardless of LRRK2 mutation status. More importantly, however, impaired olfaction was increased overall in LRRK2 carriers both with and without PD, though the impairment was only present in a subset of NMCs. Compared to controls, the mean score was lower among NMC (difference = -3.518, p = 0.006), MC (difference = -7.677, p < 0.0001), and idiopathic PD (PD-NC) (difference = -13.810, p < 0.0001). Olfaction was better among MC (PD-MC) than non-LRRK2 PD (PD-NC) (difference = 6.13, p = 0.0012). Group differences from the continuous analysis were maintained in dichotomous analysis stratifying at 15th percentile for age and gender.

CONCLUSION

Olfaction is impaired in LRRK2 G2019S-mutation related PD, although less overall than other PD. Further, olfaction is impaired in a subset of LRRK2 NMC, suggesting that olfaction may be a marker for development of PD in this group, and that longitudinal studies are warranted.

Cord blood telomere length, telomerase activity and inflammatory markers in pregnancies in women with diabetes or gestational diabetes

AIMS

We tested the hypothesis that diabetes during pregnancy leads to chromosomal DNA damage and telomere attrition in the feto placental unit and cord blood, and provides evidence for intrauterine programming towards a senescent phenotype in the offspring.

METHODS

We obtained cord blood from pregnant women with pregestational Type 1 diabetes (n=26), Type 2 diabetes (n=20) or gestational diabetes (n=71), and control subjects without diabetes (n=45, n=76 and n=81, respectively) matched for maternal and gestational age. We measured cord blood mononuclear cell telomere length, telomerase activity (a reverse transcriptase that limits telomere attrition), and concentrations of insulin, high-sensitivity C-reactive protein (hs-CRP) and soluble intercellular adhesion molecule-1 (sICAM-1).

RESULTS

We found no significant differences between groups in cord blood telomere length in any nucleated cell type, or in hs-CRP or sICAM-1 concentrations, but telomerase activity was higher in cord blood from Type 1 (P<0.05) and gestational diabetes pregnancies (P<0.05), but not in Type 2 diabetes pregnancies. There were no significant relationships between glycaemic control, cord blood telomere length, telomerase activity or inflammatory markers in any group.

CONCLUSIONS

We found no difference in cord blood telomere length in pregnancies of women with diabetes compared with control subjects, but higher cord blood telomerase activity in Type 1 and gestational diabetes. This may reflect upregulated telomere reverse transcriptase in response to in utero oxidative DNA and telomere damage. These observations are relevant to the hypothesis that diabetes during pregnancy leads to in utero preprogramming towards senescence in the offspring.

Human gene expression profiles of susceptibility and resistance in tuberculosis

Tuberculosis (TB) still poses a profound burden on global health, owing to significant morbidity and mortality worldwide. Although a fully functional immune system is essential for the control of Mycobacterium tuberculosis infection, the underlying mechanisms and reasons for failure in part of the infected population remain enigmatic. Here, whole-blood microarray gene expression analyses were performed in TB patients and in latently as well as uninfected healthy controls to define biomarkers predictive of susceptibility and resistance. Fc gamma receptor 1B (FCGRIB)was identified as the most differentially expressed gene, and, in combination with four other markers, produced a high degree of accuracy in discriminating TB patients and latently infected donors. We determined differentially expressed genes unique for active disease and identified profiles that correlated with susceptibility and resistance to TB. Elevated expression of innate immune-related genes in active TB and higher expression of particular gene clusters involved in apoptosis and natural killer cell activity in latently infected donors are likely to be the major distinctive factors determining failure or success in controlling M. tuberculosis infection. The gene expression profiles defined in this study provide valuable clues for better understanding of progression from latent infection to active disease and pave the way for defining predictive correlates of protection in TB.

Impact of age and sex on mycobacterial immunity in an area of high tuberculosis incidence

SETTING

The extent of immune reactivity measured by the tuberculin skin test (TST) and interferon-gamma (IFN-gamma) T-cell assays is usually not analysed.

OBJECTIVE

To determine the impact of age and sex on assay positivity and on the extent of reactivity of both TST and T-cell assays in young persons in an area of South Africa with high TB transmission.

RESULTS

Age had a strong impact on assay positivity for all seven immune phenotypes tested (P < 0.0007). Among positive responders, the extent of purified protein derivative (PPD) triggered IFN-gamma release (P < 0.003) was sensitive to age. ESAT-6 triggered IFN-gamma release (day 7, P = 0.03) and the frequency of PPD-specific IFN-gamma(+)CD4(+) (P = 0.03) and IFN-gamma(+)CD8(+) cells (P = 0.04) were weakly dependent on age. By contrast, the extent of TST induration was insensitive to age (P > 0.05), and sex had no significant impact on any phenotype measured (P > 0.05). The high proportion of positive responders in the 1-10 year age-group observed with long-term whole blood assays, but not with 3-day assays and TST, suggests that long-term whole blood assays may be confounded by bacille Calmette-Guérin vaccination in this age group.

CONCLUSION

There is a significant impact of age, but not sex, on different assays of immune reactivity in this high TB transmission setting.

Highly discordant T cell responses in individuals with recent exposure to household tuberculosis

BACKGROUND

There are limited data comparing interferon-gamma release assays (IGRAs) for the detection of Mycobacterium tuberculosis infection in highly endemic settings.

METHODS

A cross-sectional household contact study was conducted to measure the agreement of two IGRAs in relation to the tuberculin skin test (TST) to detect M tuberculosis infection and to assess the influence of M tuberculosis exposure and age.

RESULTS

In 82 individuals in household contact, 93% of children and 42% of adults had a high M tuberculosis contact score. The TST was positive in 78% of adults and 54% of children, the T-SPOT.TB was positive in 89% of children and 66% of adults and the QuantiFERON TB Gold (QTF) was positive in a similar proportion of adults and children (38.1% and 39.6%). In children there was poor agreement between the TST and T-SPOT.TB (kappa = -0.15) and the T-SPOT.TB and the QTF (kappa = -0.03), but good agreement between the TST and the QTF (kappa = 0.78) using 10 mm cut-off. In adults there was fair to moderate agreement between the TST and T-SPOT.TB (kappa = 0.38), the TST and QTF (kappa = 0.34) and T-SPOT.TB and QTF (kappa = -0.50). High levels of exposure to M tuberculosis were associated with at least a sevenfold odds of being T-SPOT.TB positive (95% CI 7.67 to 508.69) and a threefold odds of being QTF positive (95% CI 3.02 to 30.54). There was a significant difference in the magnitude of T-SPOT.TB early secretory antigenic target (ESAT)-6 and culture filtrate protein 10 kD (CFP-10) spot counts between adults and children.

CONCLUSIONS

The T-SPOT.TB may be more sensitive than the TST or QTF for detecting recent M tuberculosis infection in children. Differences between assays and the predictive utility of these findings for subsequent disease development should be prospectively assessed.

Characterization of maleuric acid derivatives on transgenic human monoclonal antibody due to post-secretional modifications in goat milk

A fully human antibody to tumor necrosis factor-alpha was expressed in the mammary glands of transgenic goats. The goat expressed antibody (gAb) is heterogeneous and has several isoforms due to typical cellular post-translational modifications. In addition, one post-secretional modification on gAb was discovered by high-resolution cation exchange chromatography (CIEX). The presence of these variants in the final product was shown to be dependent upon the initial milk storage and traditional purification methodologies used. These observations allow for the development of new sample recovery and purification processes to eliminate these variants. Various enzymatic treatments were used to characterize different gAb heavy chain C-terminal lysine and sialic acid variants. In addition, an unknown derivative with the additional mass of 140 Da was found in transgenic gAb using mass spectrometry (MS). The modification sites were identified as the N-termini of gAb light chains and heavy chains using Q-TOF MS. Characterization of transgenic gAb isoforms was facilitated by utilizing different enzymes, CIEX and MS techniques. A maleuric acid modification on the N-terminal portion of gAb was shown to be consistent with the available data characterizing this new derivative of transgenic gAb isoforms in goat milk.

Glycaemic control throughout pregnancy and risk of pre-eclampsia in women with type I diabetes

The aim of this study was to examine the influence of pre-pregnancy care and its effect on early glycaemic control and also the effect of glycaemic control in later pregnancy on risk of pre-eclampsia in women with type I diabetes. A prospective cohort study of 290 consecutive nonselected pregnancies in women with type I diabetes was performed from 1991 to 2002. We examined the relationship of monthly glycosylated haemoglobin (HbA1c) level, pre-pregnancy care, parity, diabetes duration, microvascular complications, maternal age, weight and smoking with risk of pre-eclampsia. Pre-eclampsia developed in 31/243 singleton births (12.8%). HbA1c level at 24 weeks was significantly increased in women with pre-eclampsia compared with women without pre-eclampsia (6.0 versus 5.6%, P= 0.017) and was, after nulliparity, the strongest independent predictor of increased risk (OR 1.65 for each 1% increase in HbA1c; P= 0.01). In contrast, there was no relationship between pre-pregnancy care or HbA1c level at booking and risk of pre-eclampsia.

Cattle and sheep farms as reservoirs of Campylobacter

AIM

This is a review of the natural Campylobacter colonization and transmission among ruminant livestock in the dairy farm environment.

METHODS AND RESULTS

Using cultural detection methods and enumeration techniques the distribution of Campylobacter in ruminant animals at birth, on the farm, at slaughter and in the farm environment have been examined. Colonization and shedding rates are higher among young animals while patterns of shedding in adult animals may be seasonal. Stored and land-dispersed slurries provide a reservoir for scavenging birds and flies and a source for runoff.

CONCLUSIONS

The dairy farm plays a significant role in the dissemination of Campylobacter subtypes that can cause disease in the human community.

SIGNIFICANCE AND IMPACT OF STUDY

An understanding of the role of the dairy farm in the environmental cycle of Campylobacter is required in order to devise intervention strategies.

Clinical trials in neuro-oncology

Clinical trials are prospective scientific studies involving human participants and form the basis for identifying new treatments for diseases like brain tumors. A clinical trial should be designed to provide definitive results for a study question. Therefore, investigators should understand the principles underlying the design, execution and analysis of clinical trials. In addition to the application of basic principles germane to the design of all clinical trials, studies in neuro-oncology also involve unique challenges in case definition, selection of endpoints and definition of response. This review begins with enumeration of the basic principles of clinical trial design including reduction of bias and variability, and concludes with a review of study design factors of particular relevance for neuro-oncology.

Do HIV type 1 RNA levels provide additional prognostic value to CD4(+) T lymphocyte counts in patients with advanced HIV type 1 infection?

Our objective was to assess whether HIV-1 RNA levels provide additional prognostic information beyond CD4(+) T lymphocyte counts in the prediction of subsequent HIV-1 disease progression among patients with advanced HIV-1 disease. In a nested case-control study conducted in patients with baseline CD4(+) T lymphocyte counts < 300 cells/mm(3) and receiving nucleoside reverse transcriptase inhibitors, 102 patients who progressed to an AIDS-defining event or death were matched within 10 CD4(+) T lymphocyte cells/mm(3) to patients who did not progress. The relationship between plasma HIV-1 RNA levels and HIV-1 disease progression was studied using conditional logistic regression analysis, which adjusts for the matching by baseline CD4(+) T lymphocytes. We observed a 0.10 log(10) copies/ml difference in baseline HIV-1 RNA levels between cases and their matched controls (p = 0.027). The relative risk for HIV-1 disease progression increased with increasing baseline HIV-1 RNA levels (odds ratio [OR] for a 3-fold higher HIV-1 RNA level, 1.42; 95% confidence interval [CI], 1.08--1.86), and remained important when also controlling for clinical status at baseline and CD4(+) T lymphocytes at 2 months (p = 0.038). Higher baseline HIV-1 RNA levels were associated with HIV-1 disease progression among patients with a baseline CD4(+) T lymphocyte count of 100 cells/mm(3) or greater (OR, 1.80; 95% CI, 1.15--2.81), but not among patients with a baseline CD4(+) T lymphocyte count < 100 cells/mm(3) (OR, 1.09; 95% CI, 0.73--1.63). We concluded that HIV-1 RNA levels predict subsequent HIV-1 disease progression independent of CD4(+) T lymphocyte counts. The magnitude and importance of the prognostic information contained in the HIV-1 RNA levels appear to depend on the CD4(+) T lymphocyte counts.

Use of pulsed-field gel electrophoresis and flagellin gene typing in identifying clonal groups of Campylobacter jejuni and Campylobacter coli in farm and clinical environments

Although campylobacters have been isolated from a wide range of animal hosts, the association between campylobacters isolated from humans and animals in the farm environment is unclear. We used flagellin gene typing and pulsed-field gel electrophoresis (PFGE) to investigate the genetic diversity among isolates from animals (cattle, sheep, and turkey) in farm environments and sporadic cases of campylobacteriosis in the same geographical area. Forty-eight combined fla types were seen among the 315 Campylobacter isolates studied. Six were found in isolates from all four hosts and represented 50% of the total number of isolates. Seventy-one different SmaI PFGE macrorestriction profiles (mrps) were observed, with 86% of isolates assigned to one of 29 different mrps. Fifty-seven isolates from diverse hosts, times, and sources had an identical SmaI mrp and combined fla type. Conversely, a number of genotypes were unique to a particular host. We provide molecular evidence which suggests a link between campylobacters in the farm environment with those causing disease in the community.

Combination nucleoside analog reverse transcriptase inhibitor(s) plus nevirapine, nelfinavir, or ritonavir in stable antiretroviral therapy-experienced HIV-infected children: week 24 results of a randomized controlled trial--PACTG 377. Pediatric AIDS Clinical Trials Group 377 Study Team

One hundred eighty-one antiretroviral-experienced, protease inhibitor-naive, clinically stable HIV-infected children between 4 months and 17 years of age were randomly assigned to receive one of four combination regimens to evaluate the change in plasma HIV RNA, safety, and tolerance when changing antiretroviral therapy to a protease inhibitor-containing combination regimen. All four regimens contained stavudine; in addition children received nevirapine plus ritonavir, lamivudine plus nelfinavir, nevirapine plus nelfinavir, or lamivudine plus nevirapine plus nelfinavir. Twelve additional children chose to receive stavudine plus lamivudine plus nelfinavir, with nelfinavir given bid, rather than tid as for the main regimens. Overall, 51% (89/176; 95% CI 43-58%) of the children on the randomized portion of the study had an HIV RNA response (< or =400 copies/ml) on at least two of the three HIV RNA determinations taken at Weeks 8, 12, and 16. At Week 24 the proportion of children with an HIV RNA response still on initial therapy was 47% (83/176; 95% CI 40-55%) and ranged from 41 to 61% for the four randomized treatment arms. Rash was frequently seen (27%) on the treatment arms containing nevirapine. At Week 24 64% (7/11, 95% CI 31-89%) of the children on the bid nelfinavir combination regimen were still on initial therapy with an HIV RNA response as compared with 46% (23/50; 95% CI 32-61%) on the corresponding tid nelfinavir combination regimen. A change in antiretroviral therapy to a protease inhibitor-containing regimen was associated with a virological response rate of approximately 50% for this patient population.

Activity of antibiotics used in human medicine for Campylobacter jejuni isolated from farm animals and their environment in Lancashire, UK

A retrospective study of 96 Campylobacter jejuni isolated from farm animals and the environment showed that most were less susceptible than the NCTC type strain to nalidixic acid (MICs 4-32 mg/L), ciprofloxacin (MICs 1-2 mg/L) and erythromycin (MICs 16-64 mg/L), but had similar susceptibility to tetracycline (MICs 4-8 mg/L) and kanamycin (MICs 4-8 mg/L). None had the high MICs of ciprofloxacin (>32 mg/L) or erythromycin (1024 mg/L) typically associated with clinical resistance in this species. Some farms used antimicrobial agents, but there was no obvious association between the use of agents and the susceptibility of the isolates.

Immunologic response to combination nucleoside analogue plus protease inhibitor therapy in stable antiretroviral therapy-experienced human immunodeficiency virus-infected children

The response of 40 immunologic parameters was studied for 147 clinically stable, protease inhibitor-naive, human immunodeficiency virus (HIV)-infected children aged 2-17 years when antiretroviral therapy was changed to either a dual nucleoside analogue regimen or a protease inhibitor-containing regimen. Immunologic response to therapy, as measured by lymphocyte subsets, 3-color flow cytometric measures, and lymphoproliferative assays, were investigated for changes in weeks 44 and 48. The most significant changes after baseline that were associated with the administration of a protease inhibitor-containing regimen were seen for percentages of CD8(+)/CD38(+)/HLA-DR(+), CD8(+)/CD95(+)/CD28(-), and CD8. The percentages of CD8(+)/CD38(+)/HLA-DR(+) and CD8(+)/CD95(+)/CD28(-) decreased from baseline medians of 33% and 46% to medians of 18% and 30% at week 44 (P<.0001 for both). Median CD4 cell count increased 168 cells/microL (from 694 cells/microL to 862 cells/microL; P=.02) by week 48 in this clinically stable population. Changes in lymphoproliferative responses to HIV antigens and recall antigens did not increase over time and between groups.

A member of the Hsp60 gene family from the peach potato aphid, Myzus persicae (Sulzer.)

A novel cDNA clone encoding a mitochondrial Hsp60 was isolated from a Myzus persicae cDNA library. The nucleotide sequence consisted of 2348 bp and contained an open reading frame (ORF) of 1722 bases. The putative protein encoded by this ORF consisted of 574 amino acids and was designated MPHSP60. Comparison of MPHSP60 with other Hsp60s found that it was most similar to Hsp60 from Culicoides variipennis (85.6% similarity). Phylogenetic analysis revealed that MPHSP60 is clustered together with other insect Hsp60s. Comparisons were also made between MPHSP60 and SymL, the GroEL homologue of Myzus persicae endosymbionts.

Nucleoside analogs plus ritonavir in stable antiretroviral therapy-experienced HIV-infected children: a randomized controlled trial. Pediatric AIDS Clinical Trials Group 338 Study Team

CONTEXT

Although protease inhibitors are used routinely in adults with human immunodeficiency virus (HIV) infection, the role of these drugs in the treatment of clinically stable HIV-infected children is not clear.

OBJECTIVE

To evaluate the safety, tolerance, and virologic response produced by a change in antiretroviral therapy in HIV-infected children who were clinically and immunologically stable while receiving previous therapy.

DESIGN

The Pediatric AIDS Clinical Trials Group 338, a multicenter, phase 2, randomized, open-label controlled trial conducted from February 6 to April 30, 1997 (patient entry period); patients were followed up for 48 weeks.

SETTING

Pediatric HIV research clinics in the United States and Puerto Rico.

PATIENTS

Two hundred ninety-seven antiretroviral-experienced, protease inhibitor-naive, clinically stable HIV-infected children aged 2 to 17 years.

INTERVENTIONS

Children were randomized to receive zidovudine, 160 mg/m2 3 times per day, plus lamivudine, 4 mg/kg 2 times per day (n = 100); the same regimen plus ritonavir, 350 mg/m2 2 times per day (n = 100); or ritonavir, 350 mg/m2 2 times per day, and stavudine, 4 mg/kg 2 times per day (n = 97).

MAIN OUTCOME MEASURE

Plasma HIV-1 RNA levels at study weeks 12 and 48, compared among the 3 treatment groups.

RESULTS

At study week 12, 12% of patients in the zidovudine-lamivudine group had undetectable plasma HIV RNA levels (<400 copies/mL) compared with 52% and 54% of patients in the 2- and 3-drug ritonavir-containing groups, respectively (P<.001). Through study week 48, 70% of children continued receiving their ritonavir-containing regimen. At study week 48, 42% of children receiving ritonavir plus 2 nucleosides compared with 27% of those receiving ritonavir and a single nucleoside had undetectable HIV RNA levels (P = .04); however, similar proportions in each group continuing initial therapy had HIV RNA levels of less than 10000 copies/mL (58% vs 48%, respectively; P = .19).

CONCLUSIONS

In our study, change in antiretroviral therapy to a ritonavir-containing regimen was associated with superior virologic response at study week 12 compared with change to a dual nucleoside analog regimen. More children receiving ritonavir in combination with 2 compared with 1 nucleoside analog had undetectable HIV RNA levels at study week 48.

[The natural history of of the antiretrovirals: the continuum of their evaluation]

Antiretroviral drugs have, as any medical therapy, their natural history. They are born by screening or designing of molecules with activity against HIV, their efficacy and safety is investigated by clinical trials, evaluated by regulatory bodies, used by clinical practice, and finally analyzed by quality of care, economic, social and ethical studies. This flow of information is dynamically accumulated, but it may stop if negative results are obtained. The described knowledge pathway implies that specific methods are needed to answer different questions. At the same time, many decisions have to be taken in order to keep the process flowing, including multiple agents, such as drug industries, government departments, clinicians, health care providers and health policy makers. This paper describes a comprehensive conceptual framework, including the "knowledge" on antiretroviral drugs, the "methodologies" needed to generate them, and the underlying processes of "decision making". It proposes the need for a continuum of assessment of these drugs.

Differential binding of the insecticidal lectin GNA to human blood cells

Evidence of snowdrop lectin binding to human white cells supports the need for greater understanding of the possible health consequences of incorporating plant lectins into the food chain.

N-glycans are not a universal signal for apical sorting of secretory proteins

In MDCK cells, N-glycans have been shown to determine the sorting of secretory proteins and membrane proteins to the apical domain in the absence of a dominant basolateral targeting signal. We have examined the sorting of endogenous proteins in ECV304 cells in the presence and absence of tunicamycin, an inhibitor of N-linked glycosylation. A prominent apically secreted protein of 71 kDa was not N-glycosylated and continued to be secreted apically in the presence of tunicamycin. In contrast, other endogenous proteins that were N-glycosylated were secreted preferentially into the basolateral medium or without polarity. When rat growth hormone was expressed in MDCK and ECV304 cells, we observed 65 and 94% of the secretion to the basolateral medium, respectively. Introduction of a single N-glycan caused 83% of the growth hormone to be secreted at the apical surface in MDCK cells but had no significant effect on the polarity of secretion of growth hormone in ECV304 cells. These results indicate that not all cell lines recognise N-glycans as a signal for apical sorting and raises the possibility of using ECV304 cells as a model system for analysis of apical sorting molecules.

Prevalence of nim genes in anaerobic/facultative anaerobic bacteria isolated in South Africa

This study investigated the prevalence of nim genes (proposed to encode a 5-nitroimidazole resistance product) in 64 anaerobic/facultative anaerobic bacteria. Employing universal nim gene primers, 458-bp amplified fragments were recorded as presumptive positives in 22/64 strains at an annealing temperature of 52 degrees C and 15/64 strains at 62 degrees C, of which seven were propionibacteria. DNA sequencing confirmed the presence of nimA genes in Propionibacterium spp. (five strains), Actinomyces odontolyticus (one strain), Prevotella bivia (one strain) and Clostridium bifermentans (one strain) and nimB genes from five strains of Bacteroides fragilis. nimA genes were predominant in propionibacteria indicating a potential nimA gene source in anaerobic environments.

A randomized study of combined zidovudine-lamivudine versus didanosine monotherapy in children with symptomatic therapy-naive HIV-1 infection. The Pediatric AIDS Clinical Trials Group Protocol 300 Study Team

OBJECTIVE

The Pediatric AIDS Clinical Trials Group (PACTG) Protocol 300 assessed the clinical efficacy and safety of combination zidovudine/lamivudine (ZDV/3TC) compared with either didanosine (ddI) alone or combination ZDV/ddI.

STUDY DESIGN

Children with symptomatic human immunodeficiency virus (HIV) infection, 6 weeks through 15 years of age, were stratified according to age and randomly assigned to receive ddI, ZDV/3TC, or ZDV/ddI. The primary endpoint was time to first progression of HIV disease or death. Enrollment in the ZDV/ddI arm stopped after 11 months on the basis of results of PACTG Protocol 152, but blinded follow-up continued.

RESULTS

For the 471 children who could be evaluated, the median age was 2.7 years, median CD4 cell count was 699 cells/mm3, and median log10 HIV RNA was 5.1/mL. Median follow-up was 9.4 months. Patients receiving ZDV/3TC had a lower risk of HIV disease progression or death than those receiving ddI alone (15 vs 38 failures, P = .0006) and a lower risk of death (3 vs 15 deaths, P = .0039). Weight and height growth rates, CD4+ cell counts, and RNA concentrations showed results favoring ZDV/3TC. For patients concurrently randomized to all 3 treatment arms, both ZDV/3TC and ZDV/ddI recipients had lower risk of HIV disease progression than those who received ddI alone (P = .0026 and P = .0045).

CONCLUSIONS

Combination therapy with either ZDV/3TC or ZDV/ddI was superior, as determined by clinical and laboratory measures, to monotherapy with ddI.

Regulation of the c-jun gene in p210 BCR-ABL transformed cells corresponds with activity of JNK, the c-jun N-terminal kinase

Activity of the c-jun N-terminal kinase (JNK) has been shown in hematopoietic cells transformed by p210 BCR-ABL. However, analysis has not been reported for hematopoietic cells on the consequences of this activity for c-jun promoter regulation within its distinctive proximal 8-base consensus CRE-like element, an element linked to JNK-mediated increase in c-jun transcription. In the present study, regulation of the proximal c-jun promoter was studied in murine myeloid cells transformed by p210 BCR-ABL. Promoter regulation in p210 BCR-ABL transformed cells was compared with regulation of the promoter in nontransformed interleukin-3 (IL-3)-dependent parental cells. The composition of nuclear AP-1 proteins contained within cells with p210 BCR-ABL, and their binding to the c-jun promoter proximal CRE-like element, was compared with the composition and binding of AP-1 proteins in IL-3-treated parental cells without p210 BCR-ABL. The present analysis found fivefold increased c-jun transcription occurring in p210 BCR-ABL transformed murine myeloid cells possessing a corresponding magnitude of increased kinase activity of JNK, compared with IL-3-stimulated parental cells. Augmented JNK activity was accompanied by increased nuclear abundance of c-jun and c-fos proteins that bound specifically to the proximal c-jun promoter CRE element. Also, representative human leukemic cell lines expressing p210 BCR-ABL and possessing abundant kinase activity of JNK, when compared with parental cells that were deficient in JNK activity, had increased c-jun and c-fos proteins. Finally, to show the relevance of these observations in model systems, we studied blast cells from patients with Philadelphia chromosome-positive acute leukemic transformation, and observed comparable activities of JNK catalysis and c-jun/AP-1 protein relative to the cell lines that possessed p210 BCR-ABL and JNK activity. These studies provide a basis for investigating the set of downstream genes which augmented c-jun/AP-1 activity enlists in the process of transformation by p210 BCR-ABL.

Isolation of Campylobacter jejuni from groundwater

A pollution event which occurred at a spring in the Arnside area of Cumbria provided an opportunity to investigate whether Campylobacter jejuni could be detected in groundwater. Hydrological evidence suggested that the source of contamination was a dairy farm situated within the hydrological catchment of the polluted spring. The microbiological quality of the polluted spring was monitored during intervals over the following 12 months and compared with others in the area. Campylobacter jejuni was isolated by filter enrichment of 500 ml and 100 ml filtered volumes of groundwater. It was not isolated in the absence of faecal indicator species. Some strains of Camp. jejuni from water had identical biotypes to strains isolated from the dairy herd. This paper reports the first isolation of Camp. jejuni from groundwater using cultural methods and supports the theory that groundwater may be a vehicle for Campylobacter transmission.

Physiological changes in insulin resistance in human pregnancy: longitudinal study with the hyperinsulinaemic euglycaemic clamp technique

OBJECTIVE

To perform measurements of insulin resistance serially in pregnancy and after childbirth in normal women.

DESIGN

Longitudinal study.

SETTING

Teaching hospital.

METHODS

Ten normal women were studied using the hyperinsulinaemic euglycaemic clamp technique before pregnancy, at 16, 26 and 36 weeks gestation, and 8 weeks after delivery. All women breastfed their infants. Insulin resistance was measured by the glucose infusion rate required to maintain the plasma glucose at 4.5 mmol/l.

RESULTS

There was a progressive increase in insulin resistance in all women as pregnancy progressed. The increase in resistance was most marked between 16 and 26 weeks of gestation, with only minimal progression thereafter. Lactation does not alter insulin resistance.

CONCLUSION

The timing and extent of changes in insulin resistance are of physiological importance because they affect all classes of maternal and fetal substrates.

Assessing the nutritional needs of the geriatric patient with diabetes

The 1994 Nutrition Guidelines reinforce that all nutritional plans for people with diabetes should be individualized, which is particularly important and necessary for elderly patients. The geriatric population poses many unique challenges to the healthcare professional due to physiological changes and many other risk factors that affect nutritional status either directly or indirectly. A thorough nutritional assessment that includes an evaluation of the potential nutritional risk factors described in this article can help in developing an effective and realistic nutritional plan for achieving and maintaining good blood glucose control and good nutritional status in geriatric patients with diabetes.

Urothelial extension of Wilms tumor presenting as a prolapsing urethral mass

We report a unique case of Wilms tumor presenting as a urethral mass in a patient with bilateral ureteral duplication. The prolapsing urothelial component was contiguous with the intrarenal Wilms tumor and consisted of fetal skeletal muscle free of blastemal or tubular elements.

Delayed gastric emptying as a factor in delayed postprandial glycaemic response in pregnancy

OBJECTIVE

To determine whether an alteration in gastric emptying contributes to an altered postprandial glycaemic response in normal pregnancy.

DESIGN

A longitudinal study in normal pregnancy and postpartum.

SETTING

Teaching hospital in Sheffield.

SUBJECTS

Primigravid women with uncomplicated pregnancies.

INTERVENTIONS

Simultaneous meal tolerance and paracetamol absorption tests.

MAIN OUTCOME MEASURES

1. Gastric emptying: maximum concentration (Cmax) and time to maximum concentration (Tmax) of paracetamol; 2. glycaemic response: Cmax, Tmax, and area under the curve of plasma glucose; 3. insulinaemic response: Cmax, Tmax, area under the curve of plasma insulin.

RESULTS

An increased, but not delayed, insulin response, and an increased initial glucose response to a test meal in the third trimester were not accompanied by any simultaneous delay in gastric emptying.

CONCLUSION

Gastric emptying does not seem to be a factor in the glycaemic response of pregnancy.

Combination and monotherapy with zidovudine and zalcitabine in patients with advanced HIV disease. The NIAID AIDS Clinical Trials Group

OBJECTIVE

To compare the safety and efficacy of continuing zidovudine therapy with that of zalcitabine alone or zalcitabine and zidovudine used together.

DESIGN

A randomized, double-blind, controlled trial.

SETTING

AIDS Clinical Trials units and National Hemophilia Foundation sites.

PATIENTS

1001 patients with symptomatic human immunodeficiency (HIV) disease and 300 or fewer CD4 cells/mm3 or asymptomatic HIV disease and 200 or fewer CD4 cells/mm3 who had tolerated zidovudine therapy for 6 months or more.

INTERVENTION

Patients were randomly assigned to receive zidovudine, 600 mg/d; zalcitabine, 2.25 mg/d; or zidovudine, 600 mg/d, and zalcitabine, 2.25 mg/d.

MEASUREMENTS

The primary end point was time to disease progression or death.

RESULTS

The median follow-up time was 17.7 months. The estimated 12-month event-free rates were 70%, 67%, and 73%, respectively, for the zidovudine, zalcitabine, and combination groups (P = 0.26). A trend analysis showed significantly lower progression rates for combination therapy compared with zidovudine therapy as the pretreatment CD4 cell count increased (P = 0.027). For patients with 150 or more CD4 cells/mm3, those receiving combination therapy were less likely to have disease progression or to die than were those receiving zidovudine (relative risk, 0.51; 95% CI, 0.28 to 0.93; P = 0.029). We observed no difference between the zalcitabine and zidovudine groups (relative risk, 0.74; CI, 0.40 to 1.36; P = 0.33). For patients with 50 to 150 CD4 cells/mm3 or fewer than 50 CD4 cells/mm3, we found no differences among the treatment groups (P = 0.69 and P = 0.57, respectively). Severe toxic effects occurred less frequently among patients with 150 or more CD4 cells/mm3.

CONCLUSIONS

We found no overall benefits of zalcitabine used alone or with zidovudine. However, a trend analysis suggested a better outcome for combination therapy compared with zidovudine as the pretreatment CD4 cell count increased.

Prevalence and patterns of use of concomitant medications among participants in three multicenter human immunodeficiency virus type I clinical trials. AIDS Clinical Trials Group (ACTG)

Data on the prevalence and patterns of use of concomitant medications among participants in three large phase III clinical trials of zidovudine (ZDV) in human immunodeficiency virus type 1 (HIV-1) infection were analyzed. Overall, 2,801 patients reported 43,331 uses of concomitant medications. Over 85% of clinical trial participants used one or more concomitant medications at some point during the study. Patients with acquired immune deficiency syndrome (AIDS) used an average of 7.1 drugs per month. Patients with AIDS-related complex (ARC) or who were asymptomatic used relatively fewer drugs: 3.1 and 2.7 per month, respectively. Fourteen percent of patients with AIDS used more than 10 concomitant medications per month. The three most commonly utilized classes of drugs were antiinfectives (57%), analgesics or antipyretics (55%), and vitamins (47%). A total of 17% of patients overall and 30% of AIDS patients used acyclovir while on trial. Consumption of prescription drugs was greater, and "over-the-counter" drugs less, among AIDS patients. Reported use of agents not approved by the Food and Drug Administration or approved drugs used for off-label indications was infrequent. Overall use of concomitant medications did not differ across demographic subgroups when corrected for disease stage at the time of enrollment. White, non-Hispanic, homosexual and bisexual men consumed significantly more antivirals and vitamins than other trial participants. Women in all three protocols took more analgesics or antipyretics than did men.(ABSTRACT TRUNCATED AT 250 WORDS)